The present invention relates to a method of recording a plurality of television signals of different programs and reproducing a desired program and to an apparatus for the same.
As satellite broadcasting services have expanded using broadcasting satellites (referred to as BS hereinafter) and communications satellites (referred to as CS), there has been an increase in service programs which often need multi-channel signal transmission. In a conventional home video tape recorder (VTR), one program can usually only be recorded at a time although the VTR can receive two or more programs which are transmitted on the multiple channels.
A technique of recording two or more programs at a time is known and is illustrated in FIG. 9(a). FIG. 9(a) is a block diagram of the apparatus capable of recording and reproducing three different audio/video signals at the same time. As shown, three input terminals 14A, 14B, and 14C are provided for receiving three different audio/video signals A, B, and C respectively. The input terminals are coupled to three input signal processors 15A, 15B, and 15C which are adapted for time dividing their respective audio/video signals A, B, and C into three rows of fields A1, B1, and C1. The input signal processors also produce three first control signals .alpha.l, .beta.1, and .gamma.1 for specifying the three field components A1, B1, and C1 respectively.
A recording sync signal processor 16 responsive to the first control signals .alpha.l, .beta.1, and .gamma.1 is provided for producing a second control signal .alpha. for determining an order for the three field components A1, B1, and C1 and a third control signal .beta. for identifying the three field components A1, B1, and C1. A recording signal processor 17 responsive to the second control signal .alpha. is provided for transmitting combinations of the field components A1, B1, and C1 grouped in a set of three different audio/video signals. A recorder unit 18 is provided for recording the field components A1, B1, and C1 and the third control signal .beta. in a given format on a magnetic recording tape as shown in FIG. 9(b).
During reproduction, a reproducing sync signal processor 21 responsive to the third control signal .beta., which has been reproduced and fed from the recorder unit 18, is provided for producing a fourth control signal .DELTA.. This signal identifies the field components A1, B1, and C1 to be reproduced at the recorder unit 18. A reproduced signal processor 19 responsive to the fourth control signal .DELTA. is provided for allocating the reproduced field components A1, B1, and C1 supplied from the recording unit 18 to three discrete channels. The reproduced field components A1, B1, and C1 of the audio/video signals are then transmitted along their channels to three output signal processors 20A, 20B, and 20C, respectively. At this point the field components of each audio/video signal are joined one to the other. A switch 22 is provided for selecting one of the three produced audio/video signals and outputting the selected reproduced audio/video signal to an output terminal 23.
In operation, the three different audio/video signals A, B, and C are time divided by their respective input signal processors 15A, 15B, and 15C into field components. Simultaneously, three of the first control signals a1, .beta.1, and .gamma.1 are produced for specifying their respective field components A1, B1, and C1 of the audio/video signals.
The three field components A1, B1, and C1 are transmitted to the recording signal processor 17 while the three first control signals .alpha.l, .beta.l, and .gamma.1 are fed to the recording sync signal processor 16. In response, the second control signal .alpha. is sent from the recording sync signal processor 16 to the recording signal processor 17 for determining a desired order of the three field components A1, B1, and C1.
The recording synch signal processor 16 also produces the third control signal .beta. which identifies the field components A1, B1, or Cl and allocates the third control signal .beta. to a pertinent recording track of a magnetic recording tape for storage.
Then, the recording signal processor 17 transmits the field components A1, B1, and C1 to the recorder unit 18 in the order determined by the second control signal .alpha.. In the recorder unit 18, the three field components A1, B1, and C1, for example, are recorded in this order into three adjacent recording tracks 26A, 26B, and 26C of the magnetic recording tape 24 as shown in FIG. 9(b). Simultaneously, the third control signal .beta. is stored in a control track 25 for use in the playback operation.
During reproduction, the field components A1, B1, and C1 of the reproduced audio/video signals are sent in the same order from the recorder unit 18 to the reproduced signal processor 19. Concurrently, the third control signal .beta. is retrieved and fed to the reproducing sync signal processor 21. In response to the third control signal .beta., the reproducing sync signal processor 21 produces the fourth control signal .DELTA. to identify the combination of the three field components A1, B1, and Cl in synchronism. The fourth control signal .DELTA. then causes the reproduced signal processor 19 to distribute the field components A1, B1, and C1 to their respective channels coupled to the output signal processors 20a, 20B, and 20C respectively. As the three channels are turned on by the switch 22, a desired audio/video signal of the reproduction will be obtained.
However, the recording/reproducing apparatus performs a decimation of data in both the audio and video components of the signal at an equal rate, thus causing dropoffs in the reproduced sounds. Additionally, its circuitry arrangement is relatively bulky in size and will most likely cost higher. When a single program has been recorded by the multi-program recording/reproducing apparatus, it is difficult to reproduce the signal in the same quality as of other single program recording/reproducing apparatuses.